This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 11 |
| 5 | 60 |
| 6 | 423 |
| 7 | 3381 |
| 8 | 29335 |
| 9 | 266703 |
| 10 | 2507232 |
| 11 | 24177705 |
| 12 | 238003111 |
| 13 | 2383370158 |
| 14 | 24217426745 |
| 15 | 249182213284 |
| 16 | 2592138293117 |
| 17 | 27225668134063 |
| 18 | 288405507217589 |
| 19 | 3078471666603235 |
| 20 | 33085393411436772 |
| 21 | 357782389095170193 |
| 22 | 3890765813426578535 |
| 23 | 42527471172438573757 |